Dust and heat shielded projector



Sept. 17, 1935. K. BRENKERT DUST AND HEAT SHIELDED PROJECTOR ATTORNEY.

Sept. 17, 1935. K BRENKERT DUST AND HAT SHIELDED PROJECTOR 2 Sheets-Sheet 2 Filed Feb. 8, 1934 INVENTOR.

ATTGRNEY.

Patented Sept. 17,1935

UNITED STATES PATENT OFFICE DUST AND HEAT SHIELDED PROJECTDR Application February 8, 1934, Serial No. 710,310

11 Claims.

The present invention pertains to certain improvements in light projectors of the type used particularly in motion picture theatres. The more recent light projectors in this class are 5 known as high intensity arc lamps, operating on a comparatively high current and using special electrodes containing cerium and other salts. The burning of such electrodes produces a considerable amount of ash in the form of fine dust,

l due to the salts contained therein, and this dust settles on the operating mechanism and other moving parts, with the result that frequent cleaning is necessary and the bearing surfaces are often clogged by the mixture of dust with the l lubricant.

Further, cleaning and adjustment must occasionally be performed in the short intervals of time occurring between films, and this operation is made still more dimcult because of the high 0 heat of the arc. It is evident also that high temperature itself is detrimental to the working parts. Simple ventilation for cooling is not possible, for the flaming type of arc produced in high intensity lamps must not be deiiected by air currents.

The principal object of Vhis invention is to alleviate these difliculties and provide a simpler and more compact assembly than is found in machines of present construction. This object is accomplished by providing a baille structure which divides the interior of the lamp housing into two chambers. The forward chamber contains the arc forming ends of the electrodes, and the operating and control mechanism is assembled in the rear or mechanism chamber. The baffle structure keeps the dust from the arc out ci' the mechanism chamber.

Several other advantages result from the provision of the baffle and other innovations embodied in the invention. For example, the mechanism chamber may be freely ventilated without disturbing the arc, inasmuchas the baiiie structure shields the arc from air currents flowing through the mechanism chamber. Because of the comparatively low temperature in the mechanism chamber, and its freedom from dust, it is practical to assemble therein certain parts, such as the'motor, which otherwise must be mounted outside of the housing. This outside mounting "0 often necessitates the shortening or elimination of one of the side doors of the lamp housing; but where the mechanism is mounted within the mechanism chamber, as in the present invention, the housing may have two full length doors so that the whole mechanism chamber, as well as the combustion chamber, is fully and readily accessible from either side. It is also evident that the assembly of all the control and regulating mechanism within the mechanism chamber and the accessibility thereof, as already pointed 5 out, results in a neat, compact and simple construction.

The baie is made of a heat conducting metal so that the heat of the combustion chamber is transferred to the mechanism chamber. The free l0 ventilation of the mechanism chamber carries off the heat from the arc and maintains this chamber as well as the back plate of the housing in a cool condition. Consequently the back plate is adapted to support various sensitive instrul5 ments such as the ammeter, the potentiometer and the control switch for the carbon feed motor. Also, the operator is not hindered by a hot back plate in manipulating the various control handles that are mounted close to the plate. 20

The invention is fully disclosed by way of an example in the following descriptionA and in the accompanying drawings in which Figure 1 is a longitudinal section of the device;

Figure 2 is a section on the line 22 of Fig- 25 ure 1;

Figure 3 is a rear end view, and

Figure 4 is a section on the line 4-4 of Figure 3.

Reference to these views will now be made by 30 use of like characters which are employed to designate corresponding parts throughout.

The lamp housing I is a sheet metal structure of more or less conventional design. It will be noted, however, that both sides are iitted with 35 double walled sheet metal doors 2. These extend the entire length of the housing as may be seen by the hinges 3 at the front of the housing in Figure 1 and the free ends 4 at the rear of the housing in Figure 2. 40

In the bottom of the housing are mounted two longitudinal guide rods or bearings 5 between which is a parallel feed screw 6. The feed screw extends through the rear wall of the housing where itis iitted with a hand crank 1 as shown in 45 Figures 1 and 3. On these parts are mounted a forward carbon holder 8 and a rear carbon carrier 9, each having a pair of plain bosses I0 riding on the rods 5 and a tapped boss or nut Il into which the feed screw 6 is threaded. The parts 60 of the feed screw engaged respectively by the nuts I l are oppositely threaded so that the rotation of the screw brings them together or separates them according to the direction of rotation. A small motor I2 is mounted in the rear part of 65 the housing and suitably geared to the feed screw, as indicated by the numeral I3 in Figures 1 and 4.

Each of the members and 6 is covered by a curved shield I4 extending the whole length of these parts and suitably supported at the ends of the housing. In the longitudinal center of the housing is a substantially concave shield or baille I5 extending transversely of the housing and suitably sec red to the shield I4 and to the base I3 of the h using as indicated by the numerals I1 and I 8 respectively in Figure 1. The lateral edges of the member I5 are flanged outwardly at I9 (Figure 4) to be engaged by the doors 2 when closed. 'I'he baille I5 further includes an upper flanged piece sloped rearwardly to extend beyond the flue or chimney for a purpose which will presently appear. A top baille 22 rests on the upper edge of the piece 20 and extends to the forward wall of the housing to which it is suitably attached and sealed. The upper baille 22 has vertical sides 23 (Figure 2) extending to the top of the flange I9. The baille 22, 23, is spaced from the top 24 and sides 25 above the housing to form an air space 26, and this space is sealed from the interior of the baille structure for a purpose which will presently appear. In keeping with the same purpose, the flue 2I extends down to the edge of an opening 21 in the top baille 22. 'Ihe chamber 28 at the rear of the shield I5 will be hereafter designated as the mechanism chamber, and the forward space as the combustion chamber 29.

A yoke is mounted in the baille I5 by means of a vertical stem 3I which extends from the yoke into a socket 32 formed in the baille. To this yoke is attached a mirror 33 by means of a cross pin 34 so that the mirror is adapted to turn on a horizontal axis. A shaft 35 extends from the front wall of the housing and is threaded through the upper part of the baille as indicated by the numeral 36 in Figure 1, to engage a lug 31 on the back of the mirror. The mirror is tilted by the manipulation of a knob 3B on the outer end of the shaft 35. Another similar shaft 39 with an external knob 39 is threaded through the baille I5 and engages an arm 3|' of the yoke 30, for turning the mirror on the vertical pivot 3|.

A similar yoke 4D has a stem 4I journaled vertically in the carrier 9. In the yoke is mounted a clamp 42 on horizontally aligned pivot pins 42. The clamp is designed to hold the rear carbon 43 which passes through the baille I5 and mirror 33 into the combustion chamber 29. The holder 8 likewise has a clamp 44 for holding the forward carbon 45 in alignment with the carbon 43. A lug 46 extends downward from the clamp 42 and is engaged by a shaft 41 threaded in the rear wall of the housing and equipped with an external knob 43. By means of this device the rear carbon 43 may be adjusted on a horizontal axis. Another similar shaft 49 (Fig. 2) and operable by an external knob 49' (Figure 3) engages an arm 50 extending laterally from the yoke 40. This shaft adjusts the rear carbon 43 at its vertical pivot 4I.

At the top of the baille I5 are formed two bearings 5I in which is Journaled a short cross shaft 52 carrying an asbestos flame shield 53. 'I'he shaft is turned by means of a longitudinal shaft 54 passing through both ends of the housing and geared to the shaft 52 as indicated by the numeral 55 in Figure 2. The shaft 54 has operating levers 56 at both ends for raising and lowering the shield, the latter being dropped to the dotted line position in Figure 1 in order to protect the mirror when striking the arc.

In the rear wall of the housing is mounted a switch 5l for controlling the motor I2 which feeds the carbons. cording to the spacing of the carbons from each other and is fully described in my co-pending application, Serial Number 685,691 flied August 18, 1933. The rear wall also supports an ammeter 58 in series with the arc.

It will now be seen that the baille I5 and its associated parts separate completely the mechanism chamber 28 from the combustion chamber 29. The separation is maintained also at the smoke outlet 2l in the top baille 22, so that the exhaust flows immediately to the ilue 2| without being permitted to pass into the chamber 28. The latter chamber which contains practically all of the operating mechanism is thus fully protected from the ash which is formed in comparatively large quantities in the burning of high intensity electrodes containing cerium salts and the like.

The bafile is made of a metal which is a good conductor of heat, such as aluminum. The heat generated by the arc is thus rapidly conducted to the well ventilated mechanism chamber and carried out of the lamp housing by the ventilating current, so that the mechanism and the back plate are kept cool. Due to the cool condition of the back plate, sensitive instruments may be mounted thereon. Also the various control handles may now be advantageously assembled close to the back plate and maintained in a cool condition.

Moreover, the separation of the lamp housing into two chambers permits unlimited ventilation of the operating mechanism Without disturbing the flame at the are, which is not possible in existing devices. For this purpose Ventilating ports 60 and 6I are formed respectively in the bottom and top of the housing. The ports in the base may be arranged to deliver air into direct contact with the baille, back plate, motor and any other parts and in the quantity desired. The currents of air flowing through these ports are entirely shielded from the combustion chamber 29 by means of the baille structure and therefore do not disturb the flame.

The protection of the mechanism chamber from the heat and dust of the arc permits the mounting of all operating mechanism therein, whereby a neat and compact assembly is provided. For example, the feed motor is ordinarily placed outside of the housing in order to be properly ventilated, but in the present instance, it may be mounted within the housing and at the same time given all the ventilation that it requires and protected from ash of the arc. In the machine herein described, with the motor mounted inside the housing, two full length doors are possible, and the entire control mechanism is quickly accessible for oiling and adjusting.

Another advantage of the baille is that it shields the operators eyes from the glare of the arc when he is required to adjust or lubricate a part in the mechanism chamber during the operation of the lamp.

Although a specific embodiment of the invention has been illustrated and described, it will be understood that various alterations in the details of construction may be made without departing from the scope of the invention as indicated by the appended claims.

What I claim is:

1. In a projector, a housing, a baille dividing rI'his switch is actuated acy said housing into a combustion chamber and a mechanism chamber, mechanism in the other chamber for supporting an electrode and controlling an arc formed in the combustion chamber, said baille being apertured for the passage of an electrode from said mechanism to said combustion chamber, and a ilue at the top of said housing and communicating with said combustion chamber, said baille closing said flue to said mechanism chamber and extending transversely of the housing and sealed against the top, sides and bottom of said combustion chamber to separate said chambers from each other and render them dust tight with relation to each other.

2. In a projector, a housing, a baille dividing said housing into a combustion chamber and a mechanism chamber, means for forming an arc in the combustion chamber, and mechanism in the other chamber for controlling said arc, said baille including a horizontal portion spaced from the top of said housing and sealed to the vertical walls thereof to form an insulating air space beneath said top.

3. In a projector, a housing, a baille dividing said housing into a combustion chamber and a mechanism chamber, means for forming an arc in the combustion chamber, mechanism in the other chamber for controlling said arc, and a door extending the full length of a side Wall of said housing and engaging a lateral edge of said baille when closed.

4. In a projector, a housing, a baille dividing said housing into a combustion chamber and a mechanismrchamber, means for forming an arc in the combustion chamber, mechanism in the other chamber for controlling said arc, and a door extending the full length of each side wall of said housing and engaging a lateral edge of said baille when closed.

5. In a projector, a housing, a baille dividing said housing into a combustion chamber and a mechanism chamber, means for forming an arc in the combustion chamber, mechanism in the other chamber for controlling said arc, a door extending the full length of each side wall of said housing, said baille having lateral flanges engageable by said door when closed.

6. In a projector, a housing, a baffle dividing said housing into a combustion chamber and a mechanism chamber, means for forming an arc in the combustion chamber, mechanism in the other chamber for controlling said arc, and a reflector supported by said baille and disposed in said combustion chamber.

'7. In a projector, a housing, a baille dividing said housing into a combustion chamber and a mechanism chamber, means for forming an arc in the combustion chamber, mechanism in the other chamber for controlling said arc, a reflector adjustably supported by said baille and disposed in said combustion chamber, and mechanism in said' mechanism chamber for adjusting said arc and. said reflector.

8. In a projector, a housing, a baille dividing said housing into a combustion chamber and a mechanism chamber, means for forming an arc in the combustion chamber, mechanism in the other chamber for controlling said arc, a reflector adjustably supported'by said baille and disposed in said combustion chamber, mechanism in said mechanism chamber for adjusting said arc and said reflector, and an electrode feeding motor in said mechanism chamber.

9. In a projector, a housing, a baille dividing said housing into a combustion chamber and a mechanism chamber, means for forming an arc in the combustion chamber, mechanism in the other chamber for controlling said arc, a. feed screw and a pair of guide rods extending lengthwise of said housing and disposed of beneath said baille, electrode holders mounted on said screw and rod and disposed respectively in said charnbers, shields mounted over said screw and rods in said combustion chamber, mechanism in said mechanism chamber for regulating said arc, a reflector adjustably supported by said baille and disposed in said combustion chamber, manual mechanism in said mechanism chamber for adjusting said arc and said reflector, and an electrode feeding Amotor in said mechanism chamber.

10. In a projector, a housing, a baille dividing said housing into a combustion chamber and a mechanism chamber, mechanism in the other chamber for supporting an electrode and controlling an arc formed in the combustion chamber, said baille being apertured for the passage of an electrode from said mechanism to said combustion chamber, said baille extending transversely of the housing and sealed against the top, sides and bottom of said combustion chamber to separate said chambers from each other 40 and render them dust tight with relation to each other, said baille consisting of a material which is a good conductor of heat, and means for ventilating said mechanism chamber.

11. In a projector, a housing, a baille dividing said housing into a combustion chamber and a mechanism chamber, mechanism in the other chamber for supporting an electrode and controlling an arc formed in the combustion cham-v ber, said baffle being apertured for the passage of an electrode from said mechanism to said combustion chamber, said baffle extending transversely of the housing and sealed against the top, sides and bottom of said combustion chamber to separate said chambers from each other and render them dust tight with relation to each other, said baille consisting of a material which is a good conductor of heat, and Ventilating ports formed in said housing at said mechanism chamber.

KARL BRENKERT. 

